Uncertainty Lab.

Purpose.

To find out the uncertainty of certain measurements using certain pieces of equipment.

Data Table.

Calculations.

Conclusion.

In conclusion, not all of the data was accurate. The average deviation in the boiling water part of the experiment was 2.8°C, which was extremely high for a gap between numbers. The average deviation for the freezing water was 0.5°C. For the 20g weight it was 0.27g, for the 10mL graduated cylinder with water it was 0.87g and for the 100mL graduated cylinder with water it was 0.49g. All of the data was a normal amount of spread except for the boiling water wich almost makes that part of the data look questionable.

Discussion of Theory.

The Uncertainty Lab was done to prove that in each experiment, there is a certain amount of information that scientists are unsure about. In order to accurately measure, equipment must all have the same range of uncertainty or acceptable answers. If data is compared from different pieces of equipment, it will not be accurate because each piece of equipment has a different level of uncertainty. In order to be accurate, the same piece of equipment must be used each time. Before using a piece of equipment in an experiment, you will find the range of uncertainty. For example, if you are using a balance to measure a 20g weight, the range of uncertainty should be ±1g. This means that you are unsure about how the balance will measure the weight. If the weight is measured as 19.5g, you know the new uncertainty range for the scale is ±0.5g. You can use the new data to help in future experiments.

Sources of Error.

- The water was tainted which caused the boiling point to lower.- There was already water in the graduated cylinder causing the weight to be inaccurate.- The water that the temperature was taken from was not completely frozen, it was just ice water. If it had been completely frozen the data would have been different.

Post-Lab Questions.

1. The uncertainty of different equipment is varied. This causes even something with a set weight like a 20g weight to weight something different.2. The 10mL graduated cylinder has a smaller uncertainty due to the small increment. The 100mL has an increment of 5mL so it's harder to see the exact measurement. The 10mL has the smallest increment of 0.1mL which allows a scientist to measure better. The uncertainty of the 100mL graduated cylinder was ±5mL while the 10mL graduated cylinder has an uncertainty of ±0.1mL.3. Based on the results, the balance was more accurate. This is known because the average deviation for the 10mL graduated cylinder was 0.87mL and for the 100mL graduated cylinder it was 0.49mL while for the 20g weight on the balance it was only 0.27g.4. There were no clear outliers though there was one that was questionable. Because it was not a clear outlier, it continued to be used in the data. There were no outliers.5. If the uncertainty of a balance is ±0.005g, you must use one significant figure. This means that if the scale reads 8g, your final answer will be 8g.6. If you need to measure 9mL, the most appropriate piece of equipment to use would be a 10mL gradauted cylinder. The ticks of increase are very small so the actual reading will be more likely to be correct. It also has a smaller range of error, only ±0.1mL.